Duck billed platypus belongs to ………….. While kangaroo belongs to ………….. .

Explanation

**Step-by-Step Solution:**

1. **Identify the Duck-billed Platypus Classification:**
- The Duck-billed Platypus is classified under the subphylum **Prototheria**. This classification is significant because it indicates that the platypus is one of the few egg-laying mammals.

2. **Identify the Kangaroo Classification:**
- The Kangaroo belongs to the subphylum **Metatheria**. This classification is important as it refers to mammals that give birth to relatively undeveloped young, which then continue to grow in a pouch.

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